BREXIT may be blocked by half a million Irish citizens living in Britain, Remain campaigners have shockingly claimed.
Citizens from the Republic of Ireland living in Britain are allowed to vote in June's referendum — the only EU country other than Commonwealth nations Malta and Cyprus granted this privilege — and experts have warned that their impact could win the fight for the Remain campaign.
A recent online poll of nearly 25,000 Irish people has revealed the country overwhelmingly supports Britain remaining in the EU, with a 17 point lead over those who support Brexit.
In such a tight race, hundreds of thousands of Irish immigrants voting en masse could decide the referendum — and Remain campaign groups like Irish4Europe are now desperately trying to mobilise this demographic as polling day approaches.
Brian O'Connell, founding member of the group and a UK director for the British-Irish Chamber of Commerce, told Express.co.uk the Irish vote could have a huge influence on whether Ireland stays in the EU.
He said: "There are 500,000 first generation Irish in Britain — people who were born in the Republic and have moved over.
"When you consider second and third generation you're talking in the millions. I don't know if it is the largest ethnic minority but it's got to be close.
"It is a tight debate, very tight. I have followed a lot of referenda and they can be won and lost in a couple of weeks, it could change overnight. It is a tight contest and in a tight contest a few hundred thousand votes could swing it."
He argued Irish voters had a multitude of economic reasons to vote against Brexit, which he said could damage the British-Irish trade's 400,000 jobs and €1billion weekly income.
Mr O'Connell said: "Britain is Ireland's number one trade partner and I think Ireland is Britain's fifth. But Britain exports more to Ireland than to China, India and Brazil combined.
"As well as that there are 200,000 jobs provided by the British-Irish economy on both sides of the Irish Sea — 400,000 is a lot of jobs."
He said Brexit could also affect the border between Northern Ireland and the Republic — the only land border Britain would have with the EU should it vote to leave.
He said: "There is an open border at the moment. Over the last two decades, British and Irish politicians have worked very hard to make it safe, helped by a shared membership of the EU. This would be put at risk if they leave.
"Immigration is a big issue in this referendum. What would happen at the border? It is 300 miles long. Do you police it, increase border controls?"
James McGrory, Chief Campaign Spokesman for Stronger In, echoed these claims.
He said: “Leaving the EU could see the huge step backwards of border controls returning to the Irish border. This would hamper the daily lives of thousands of people who cross the border to travel to work, visit their family and do their shopping.”
These claims have been blasted as Project Fear tactics, with some critics arguing that Ireland would actually benefit from Brexit.
Should Britain leave the EU, Ireland will emerge as the only English-speaking country in the union — a quirk which would raise its profile as a base for foreign direct investment.
Despite this potential boost, the Remain's Irish campaign looks set to increase in the lead-up to the referendum. Earlier this month, Tony Blair's former spin doctor Alastair Campbell urged a crowd in Dublin: "Get stuck in — my country needs you."
Brexit could succeed or fail depending on whether Irish voters in Britain listen to these calls.